Elidir Fawr

Elidir Fawr is one of the Welsh 3,000ft mountains, with stunning views across the Carneddau, Glyderau, Tryfan, Snowdon and out to sea with Anglesey and beyond in sight.

Home to the amazing Electric Mountain renewable energy source, Elidir Fawr is one of the best mountains Snowdonia has to offer walkers and runners.

The turquoise waters of man made reservoir Marchlyn Mawr sit within the glacial bowl at Elidir’s north east side. This lake is the key part of the hydro electric power station contained deep with Elidir Fawr.

To the south and west are the twin lakes Llyn Peris and Llyn Padarn, with the town of Llanberis looking up at Elidir’s summit. This side of the mountain is also home to Dinorwic Slate Quarry, once a thriving hub of industry these split levels and slate rock faces provide explorers with endless fun. 

Elidir Fawr Trail Routes

We’ve currently got two trail routes available for Elidir Fawr. The first route below is the popular Marchlyn Mawr Loop that also takes in the nearby summits of Carnedd Y Filiast and Mynydd Perfydd. The second is our West Side Summits trail route that starts and ends in Ogwen Valley with over 3,000ft of ascent over 11 miles.

Marchlyn Mawr Loop

This fantastic Elidir Fawr loop takes in 3 neighbouring mountains, as well as offering amazing views in all directions. Watching the Snowdon Horseshoe from the Elidir Fawr summit can be an incredible experience.

Distance 5.9 miles

Time 3 hours (walking) 1 hour 20 mins (running)

Total Ascent 2,288ft

OS Maps click to open this route on the OS Maps website

Summits Elidir Fawr, Y Fronllwyd, Carnedd Y Filiast, Mynydd Perfydd.

Views Ogwen Valley, the Glyderau, the Carneddau, the Irish Sea, Snowdon Horseshoe, Welsh coastline.

Elidir Fawr Loop 3D Map | The Frozen Divide

1. Parking at a dead end lane just outside the village of Deiniolen, we take the tarmac reservoir road up to Marchlyn Mawr reservoir. At the reservoir the path there’s a clear stile and single track heading up Y Fronllwyd.

2. The trail then bears right, over the summits of Carnedd Y Filiast (great view of Elidir Fawr from here) and Mynydd Perfydd (great view of Ogwen Valley from here).

3. Continuing around the valley bowl, keeping Marchlyn Mawr on our right, we ascend the craggy path to Elidir Fawr summit. The 360 degree views from here are incredible, taking in Snowdon Horseshoe in one direction and the North Wales coastline in the other.

4. From the summit there’s a scree path that descends to the right, then it’s some hill wandering down to the top of the old quarry. An explore of the quarry leads us back to pretty much where we started.

Elidir Fawr Photo Gallery

How To Find Elidir Fawr

Check out our trail routes above for hiking or trail running at Elidir Fawr.